Journal of Geophysical Research: Biogeosciences最新文献

{"title":"Salinity and Turbidity Gradients Driven Spatial Heterogeneity of Phytoplankton Community in the Eutrophic Macrotidal Qiantang River-Estuary-Coastal Sea Continuum","authors":"Lin Zhan,&nbsp;Mengjia Zhang,&nbsp;Bo Kang,&nbsp;Hao Chen,&nbsp;Cunwang Lin,&nbsp;Huajun Zhang,&nbsp;Zhi Yang,&nbsp;Bin Wang,&nbsp;Degang Wang,&nbsp;Wei Huang,&nbsp;Jiangning Zeng,&nbsp;Yuanli Zhu,&nbsp;Zhibing Jiang","doi":"10.1029/2025JG008945","DOIUrl":"https://doi.org/10.1029/2025JG008945","url":null,"abstract":"<p>The river-estuary-coastal sea continuum is usually characterized by drastic tidal fluctuations and significant spatial gradients in salinity, turbidity, and nutrients. However, the response of the phytoplankton community in the continuum to such physicochemical variations remains poorly understood. Here, three cruises in dry, dry-to-wet transition, and wet seasons during 2022–2023 were conducted to explore the spatial variation in phytoplankton community and its main drivers in the eutrophic, macrotidal Qiantang River-estuary-coastal sea continuum. Our results revealed notable spatial heterogeneity in phytoplankton community composition across four subregions (i.e., tidal freshwater zone, upper estuary, middle estuary, and lower estuary). Generalized additive models showed that the spatial variation in phytoplankton abundance was largely explained by physical properties (i.e., salinity and turbidity). Redundancy analysis further confirmed that salinity and turbidity explained more variation in community composition than nutrients. The significant distance-decay relationship indicated that dispersal limitation profoundly influences the spatial distribution pattern of the phytoplankton community. Deterministic processes dominated community assembly in the continuum, and the relative importance of environmental filtering and stochastic processes in structuring the phytoplankton community varied across seasons. Variation partitioning analysis confirmed that the biogeographical pattern of phytoplankton was largely conditioned by the spatially structured environmental variations. These findings highlight the contributions of environmental filtering and neutral processes in shaping the spatial distribution of phytoplankton and enhance our understanding of how pronounced environmental gradients, such as salinity fluctuations and the turbidity maximum zone, regulate the spatial variation of the phytoplankton community in the macrotidal river-estuary-coastal sea continuum.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 10","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Volatile Organic Compound (VOC) Exchange in Tropical Leaf Litter in Response to Wetting: An Automated Scheme to Classify Flux Pulse Dynamics","authors":"Lia Crocker,&nbsp;Jessica Guo,&nbsp;Jana M. U’Ren,&nbsp;Giovanni Pugliese,&nbsp;S. Nemiah Ladd,&nbsp;Christiane Werner,&nbsp;Laura K. Meredith","doi":"10.1029/2025JG008774","DOIUrl":"https://doi.org/10.1029/2025JG008774","url":null,"abstract":"<p>Leaf litter emits volatile organic compounds (VOCs) that can impact atmospheric and soil processes, particularly in ecosystems with episodic litterfall and decomposition such as dry-wet transitions in tropical forests. Litter VOCs may originate from both plant and microbial sources that are challenging to disentangle but may be reflected in the temporal patterns of litter VOC fluxes to wetting. Here, we collected <i>Clitoria fairchildiana</i> litter after an ecosystem-scale experimental drought in the Biosphere 2 Tropical Rainforest and measured litter VOC fluxes over a 10-day incubation to: (a) identify and quantify litter VOC fluxes; (b) examine the impacts of moisture; and (c) distinguish plant from microbial VOCs. In total, we observed 121 masses exhibiting either significant emission (88%) or uptake (12%) fluxes. Emissions of methanol, acetaldehyde, and acetone were the dominant fluxes. Wetting dry litter altered the flux of 47% of VOCs: 66 decreased to pre-wetting levels within 24 hr although 25 sustained higher emission rates. We categorized VOCs during wetting as plant derived (55%), microbial-derived production (21%), microbial uptake (12%), and unknown (13%) by visual inspection of the flux time series. Automated classification of the wetting pulses with fitted model parameters was consistent with the visual categorization approximately 80% of the time. Our results provide measurements of litter VOC fluxes for a widespread tropical plant. Moreover, we illustrate an automated data-model approach to efficiently characterize and categorize trace gas pulses for litter VOC fluxes that is translatable to other types of trace gases, forcings, and ecosystem components including soil.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 10","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Highly Resolved Surface Phytoplankton Community Composition Along the British Columbia Coast, Derived From In Situ Hyperspectral Radiometry","authors":"Perumthuruthil Suseelan Vishnu,&nbsp;Justin Del Bel Belluz,&nbsp;Hongyan Xi,&nbsp;Midhun Shah Hussain,&nbsp;Astrid Bracher,&nbsp;Maycira Costa","doi":"10.1029/2025JG008956","DOIUrl":"https://doi.org/10.1029/2025JG008956","url":null,"abstract":"<p>Quantitative measurements of phytoplankton community composition (PCC) are essential for understanding fisheries production, ocean nutrient cycling, and the export of particulate carbon to the ocean interior. However, these measurements are constrained in dynamic coastal waters due to the spatial-temporal constraints of in situ sampling, difficulty quantifying communities, and the challenges of deriving community compositions via satellites. Here, we work to address these issues by using highly resolved in situ hyperspectral radiometry, along a ship of opportunity track through Case-2 waters of the Strait of Georgia (SoG) British Columbia, to derive phytoplankton community composition. First, an empirical orthogonal function (EOF)-based algorithm was developed using HPLC CHEMTAX-derived phytoplankton group-level chlorophyll-a (Chla) and Total Chla (TChla) concentrations and corresponding principal components derived from hyperspectral remote sensing reflectance. Second, the outputs were evaluated using cross-validation, showing good retrievals for TChla and the regionally dominant phytoplankton groups: diatoms, cryptophytes, green algae, and raphidophytes, which followed expected spatial-temporal trends with diatom-dominated spring blooms and succession to high diversity flagellate-dominated summer conditions. Furthermore, the outputs captured fine spatial scale trends including strong harmful raphidophyte blooms over the narrow transition to low salinity Fraser River plume influenced waters. These findings highlight the potential of using highly resolved hyperspectral radiometry to derive fine-scale trends in phytoplankton group level community composition in optically dynamic coastal waters. Coupled with additional measures, this method could provide valuable information on phytoplankton dynamics in the SoG, which is a critical habitat for a high diversity of pelagic fish species, including Pacific salmon.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 10","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JG008956","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Increased Heavily Silicified Diatoms Modulate the Biogenic Silica Deposition in the Yellow Sea","authors":"Mengfan He,&nbsp;Hao Zhou,&nbsp;Xiaofeng Wang,&nbsp;Xiaowei Dong,&nbsp;Yujue Wang,&nbsp;Dongyan Liu","doi":"10.1029/2025JG008790","DOIUrl":"https://doi.org/10.1029/2025JG008790","url":null,"abstract":"<p>Diatoms are the most important organisms driving the marine biogenic silica (bSi) cycle, but their biomass and species composition have undergone substantial changes in the modern ocean. How their variations affect the marine bSi cycling remains unclear. Here, we estimated the seasonal relationship between diatom assemblages and bSi content, using the data from the sediment trap, in situ observations, and surface sediments in the Yellow Sea. Monthly sediment trap data revealed a significantly positive correlation between the proportion of heavily silicified diatom <i>Paralia sulcata</i> and bSi content, indicating the contribution of diatom silicification to bSi production. Seasonal observations revealed higher bSi content and burial efficiency in summer (1.13 ± 0.38%, 57.4 ± 25.7%) than in spring (0.86 ± 0.17%, 25.3 ± 5.2%), although spring diatom concentrations are 1.5 to 2 times higher. In contrast to spring hydrodynamic conditions, which can enhance the vertical mixing and favor bSi recycling, summer stratification constrains abundant <i>P. sulcata</i> and other diatoms living below the mixed layer. This not only promotes bSi production but also facilitates their deposition and burial in sediments. The results provide important insights into the effects of diatom species shifts on bSi cycling and indicate that the seasonal dominance of heavily silicified species in the diatom community, associated with hydrodynamic sedimentary conditions, could greatly affect the bSi cycling in the modern ocean.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 10","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Carbon Isotope Constraints on Plant Water Use Efficiency in a Tropical Invaded Ecosystem","authors":"Ya-Xin Yan,&nbsp;Chao-Chen Hu,&nbsp;Yan-Bao Lei,&nbsp;Yun-Hong Tan,&nbsp;Xue-Yan Liu","doi":"10.1029/2025JG008997","DOIUrl":"https://doi.org/10.1029/2025JG008997","url":null,"abstract":"<p>Exotic plant invasions have caused substantial changes in plant diversity and the functioning of terrestrial ecosystems. One of the key determinants of plant invasion success is its resource utilization strategy, such as water utilization strategies. However, how iWUE differs between exotic and native plants, and between natives under invasion and non-invasion, remains unclear, limiting our understanding of the role of water use strategies in plant invasion and coexistence. In this study, leaf <i>δ</i>¹³C was measured to quantify the iWUE of 19 native C₃ and nine native C₄ species under no invasion, two exotic C₃ species (<i>Ageratina adenophora</i> and <i>Chromolaena odorata</i>), and 16 C₃ and 10 C₄ co-occurring natives in a tropical ecosystem of southwestern China. The significantly higher iWUE of invading plants compared with co-occurring C₃ species was associated with their invasion success and spread. Under invasion, the iWUE of coexisting native C₃ plants decreased by 42 ± 30% possibly due to enhanced water losses associated with nitrogen acquisition. Oppositely, native C₄ plants increased their iWUE by 65 ± 140%, along with enhanced photosynthetic N and NH₄⁺ assimilations, which supported greater productivity. These results highlight the critical role of water use and its coupling with other resource use strategies in facilitating exotic plant invasion and promoting native plant coexistence. This work is of great significance for advancing the understanding of mechanisms shaping plant community composition and for informing the management of water and nutrient resources to control exotic plant invasion and sustain plant diversity in tropical ecosystems.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 10","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Production of Oxygen- and Sulfur-Containing Volatile Organic Compounds by Marine Bacteria From Coastal Seawater","authors":"Yuko Omori,&nbsp;Toshiki Takahashi,&nbsp;Shigeki Wada,&nbsp;Takeo Hama,&nbsp;Satoshi Inomata,&nbsp;Hiroshi Tanimoto","doi":"10.1029/2025JG008969","DOIUrl":"https://doi.org/10.1029/2025JG008969","url":null,"abstract":"<p>Previous studies primarily examined volatile organic compound (VOC) production and consumption in isolated cultures or bulk seawater. In contrast, this study focused on natural bacterial assemblages, excluding phytoplankton, to elucidate bacterial contributions to VOC cycling in marine ecosystems. Marine bacteria have traditionally been viewed as contributors to the degradation of oxygenated volatile organic compounds (OVOCs), with their role as producers being less understood. By incubating marine bacterial assemblages with ¹³C-glucose as a carbon source, we identified VOC production derived exclusively from bacterial metabolic processes with distinct VOC profiles generated during different phases. During glucose drawdown, marine bacteria contributed to acetaldehyde production at a net production rate of 6.5 nM d⁻¹ despite functioning as rapid decomposers with a turnover time of 1.0 days. After glucose drawdown, acetone was produced at a rate of 84.0 nM d⁻¹ with a much lower degradation rate at 2.1 nM d⁻¹ and a turnover time of 68 days, suggesting that bacteria play a greater role in acetone production than degradation. Sulfur-containing VOCs (VOSCs), including dimethyl sulfide (DMS) and methanethiol, were also produced after glucose drawdown. These findings suggest that natural bacterial assemblages can generate acetone and VOSCs from their metabolic byproducts. By revealing the dual role of marine bacteria as both producers and degraders of VOCs, this study advances our understanding of their broader ecological and biogeochemical significance.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 10","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JG008969","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Statistical Identification of Nitrous Oxide Hot Moments and Their Significance Across Global Agroecosystems","authors":"Ryan Ackett,&nbsp;Haileab Hilafu,&nbsp;Ilya Gelfand,&nbsp;Debasish Saha","doi":"10.1029/2025JG008953","DOIUrl":"https://doi.org/10.1029/2025JG008953","url":null,"abstract":"<p>Nitrous oxide (N₂O) emissions from agricultural soils contribute ∼4% of total anthropogenic greenhouse gas emissions globally. Events known as “hot moments” can occur following environmental changes that favor N₂O production, which contribute disproportionately to annual cumulative emissions. Despite their significance, hot moments and their impact have not been statistically well defined, particularly on a global scale. We collected 13,787 soil N₂O flux measurements from 42 publications and evaluated 14 methods of statistical anomaly detection for their ability to identify hot moments within data sets. Two methods achieved the highest overall performance by Matthews correlation coefficient (MCC): median absolute deviation (MCC: 0.80) and minimum covariance determinant (MCC: 0.80), the latter of which also performed evenly across highly dissimilar data sets and identified more contextually important minor hot moments (39%) that other methodologies may misidentify. Interquartile range, which has previously been used and recommended, performed poorly when hot moments were either very rare or very common within a data set and identified few local hot moments (14%). Overall, hot moments comprised ∼19% of measurements while contributing ∼75% of cumulative emissions. The median background N₂O emission reported in all data sets was 2.2 g N ha⁻¹ day⁻¹, whereas the median hot moment emission was 10-fold higher, ranging from 23 to 25 g N ha⁻¹ day⁻¹. These findings advance knowledge of how to accurately define and identify hot moments globally—a crucial task to investigating and mitigating these critical biogeochemical events.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 10","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Copula-Based Cosimulation for Simulating Temporal or Spatial Data in Biogeosciences","authors":"Van Huong Le,&nbsp;Rodrigo Vargas","doi":"10.1029/2025JG008802","DOIUrl":"https://doi.org/10.1029/2025JG008802","url":null,"abstract":"<p>Accurate modeling of dependencies between variables of interest is imperative for understanding biophysical processes and mechanisms relevant to biogeosciences research. This study presents copula-based cosimulation (CopCoSim) as an approach to model the temporal or spatial joint distributions of multiple variables by capturing their dependencies and correlations. We compared CopCoSim with the traditional Sequential Gaussian CoSimulation (SGCoSim) technique through two applications, representing one (i.e., time) and two dimensions (i.e., space) on a topic relevant to biogeosciences. Specifically, we present an application for soil CO₂ efflux, which is a major flux in the global carbon budget, using two case studies: (a) temporal distribution of soil CO₂ efflux and temperature and (b) spatial distribution of soil CO₂ efflux and temperature across the conterminous United States (CONUS). The methodology involves three steps: selecting a representative training data set, applying stochastic simulation methods, and evaluating model performance. The results indicate that CopCoSim provides a more accurate model with higher precision for representing variables of interest. CopCoSim better reproduces the univariate probability distribution, temporal or spatial autocorrelation, and dependency relationships between the predictor and response variables. Because CopCoSim does not rely on linear correlation structures and normality assumptions, it captures complex dependence structures and behaviors among variables. We propose that CopCoSim is useful for research in biogeosciences, where variables of interest (e.g., soil CO₂ efflux and temperature) are often interdependent and exhibit complex temporal or spatial patterns.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 10","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JG008802","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Significant Decrease in Sedimentary Organic Carbon Sequestration in the Lower Bengal Fan During the Last Sea Level Rise","authors":"Chengpeng Sun,&nbsp;Huawei Wang,&nbsp;Gang Hu,&nbsp;Tianyi Nie,&nbsp;J. Paul Liu,&nbsp;Jian Lin,&nbsp;Wenfeng Ning,&nbsp;Xinxin Li","doi":"10.1029/2025JG008948","DOIUrl":"https://doi.org/10.1029/2025JG008948","url":null,"abstract":"<p>Deep-sea fans represent the largest sediment and organic carbon (OC) accumulation zones on Earth. However, variations of sedimentary OC sequestration in deep-sea fans during the last sea level rise have not been well evaluated. Here, a gravity core (4.24 m) retrieved from the inner flank of the active channel in the Lower Bengal Fan was analyzed for mineralogy, inorganic elements, total OC (TOC) and carbon isotopes (δ¹³C, Δ¹⁴C), and lignin phenols to reconstruct sources and accumulation rates of sediment and OC over the past 15 ka. The results showed significantly higher TOC accumulation rate (TOC_AR, 443 ± 221 mg/cm²/ka), terrestrial OC proportion (53 ± 5%), and burial efficiency (37 ± 8%) during sea-level lowstand (15–10 ka) than the following sea-level highstand (10–2 ka, 7 ± 2 mg/cm²/ka, 39 ± 6%, 22 ± 4%) due to considerable decline of terrestrial sediment and OC supply when the sea level was high. This was further evidenced by decreasing lignin content (0.46 ± 0.30 vs. 0.02 ± 0.02 mg/100 mg OC) and pre-depositional age (4,607 ± 300 vs. 2,650 ± 933 years). At 2–0 ka, slight increase in these parameters was most likely due to enhanced anthropogenic interference. The re-evaluated TOC_AR and burial efficiency for global deep-sea fans during the Holocene and the last deglaciation are higher than for deep-sea plains (&gt;1,000 m) and upwelling regions, suggesting deep-sea fans are hotspots of OC sequestration. This study highlights the role of active channels of deep-sea fans in modulating OC biogeochemistry under global climate change.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 10","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Changes in Pyrogenic Tracers Over the Last 15,000 Years in the Congo River Catchment Through Multi-Method Analysis","authors":"Samuel D. Katz,&nbsp;Helena Osterholz,&nbsp;Riley Barton,&nbsp;Ellen R. M. Druffel,&nbsp;Xiaodong Gao,&nbsp;Caroline A. Masiello,&nbsp;Cristina Santin,&nbsp;Tassiana S. G. Serafim,&nbsp;Sasha Wagner,&nbsp;Matthias Zabel,&nbsp;Rainer Lohmann","doi":"10.1029/2025JG008772","DOIUrl":"https://doi.org/10.1029/2025JG008772","url":null,"abstract":"<p>Black carbon (BC), the most recalcitrant part of the pyrogenic carbon continuum, is formed by the incomplete combustion of biomass and fossil fuels. Methods for detecting BC include the chemical degradation of condensed aromatic compounds into benzenepolycarboxylic acids (BPCA), chemothermal oxidation of organic carbon at 375°C (CTO), ¹³C nuclear magnetic resonance combined with a molecular mixing model, thermogravimetry-differential scanning calorimetry, and the use of polycyclic aromatic hydrocarbons as tracers. However, there is limited knowledge about the comparability of these methods in marine sediments and their suitability as wildfire proxies. Here, we examined a sediment core from the Congo River outflow using a multi-methodological approach with environmental data and proxies to assess pyrogenic tracers from the Congo River basin over the last 15,000 years and determine commonalities between the methods. Despite differing analytical windows, both dry-weight and total organic carbon concentrations, and δ¹³C values for most methods showed a congruous trend. Higher BC concentrations and higher δ¹³C values were present during arid periods and lower during humid periods, reflecting changes in vegetation and terrestrial organic matter inputs. For all methods, the sedimentation flux identified significant variations in BC deposition only in the last 1,000 years BP due to anthropogenic land use changes. These findings deepen our understanding of BC in the global carbon cycle and show that BC proxies can reveal distinct transport pathways, with CTO-BC representing atmospheric deposition and BPCA-BC and NMR-BC indicating fluvial inputs to coastal margins, aiding in the reconstruction of past climates and landscapes.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 10","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JG008772","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145224196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}